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Effects of SiO 2 Nanoparticles on Wettability and CO 2 –Brine–Rock Interactions in Carbonate Reservoirs: Implications for CO 2 Storage

2024; American Chemical Society; Volume: 38; Issue: 2 Linguagem: Inglês

10.1021/acs.energyfuels.3c03356

1520-5029

Yongsheng Tan, Qi Li, Liang Xu, Chikezie Chimere Onyekwena, Tao Yu, Lifeng Xu,

Hydrocarbon exploration and reservoir analysis

Nanoparticles effectively enhance the CO2 geological storage capacity by altering wettability during CO2–brine–rock interactions, which significantly impacts the CO2 residual trapping and migration in reservoirs. However, the effect of nanoparticles on CO2–brine–rock interactions in carbonate formations is poorly understood. Therefore, in this study, the impact of SiO2 nanoparticles (SNPs) on CO2–brine–rock interactions was evaluated under supercritical CO2 conditions (60 °C and 12 MPa) by analyzing wettability, conducting X-ray diffraction, scanning electron microscopy analyses, measuring weight loss, and performing low-field nuclear magnetic resonance (LFNMR) tests. The results indicated that (a) both CO2–brine–rock interactions and SNPs–CO2–brine–rock interactions can alter the wettability of carbonate rock surfaces from oil-wet to water-wet and that the carbonate rock became more water-wet after SNPs addition; (b) CO2–brine–rock interactions primarily involved the dissolution of calcite in carbonate rocks under acidic conditions, but SNPs–CO2–brine–rock interactions were more intense; (c) based on LFNMR analysis, the pores of the carbonate core in this study were divided into small pores (T2 < 5 ms) and large pores (T2 > 5 ms), with CO2–brine–rock interactions occurring mainly in the large pores of the carbonate cores but with enhanced interactions in small pores; (d) CO2 solubility in solution after CO2–brine–rock interactions increased with increasing pressure and eventually reached equilibrium, and this trend was observed both in the CO2–brine–rock system and the SNPs–CO2–brine–rock system. However, the CO2 solubility in the SNPs–CO2–brine–rock system was greater than that in the CO2–brine–rock system.